The same here.
Amarok plays well, kaffeine not.
If I open kaffeine from konsole, I found this error in konsole

Code:

mauro@aptosid:~$ LANG=C kaffeine
mauro@aptosid:~$ params.c:OpenConfFile() - Unable to open configuration file "/home/mauro/.smb/smb.conf":
No such file or directory
params.c:OpenConfFile() - Unable to open configuration file "/etc/samba/smb.conf":
No such file or directory
getnodeadd: Can not open /etc/decnet.conf

I can confirm the problem with kaffeine. I know it uses the xine backend, and that must be where there is a problem. Kaffeine starts correctly when I launch it, but it won't open an audio file for playing.

Amarok and other players are OK. Flash plays on my system, and radiotray is working, so I think all the phonon/pulseaudio parts are OK.

I did apt-cache depends for kaffeine and all the dependencies are installed, so it must be something broken in xine world.